1. Field of the Invention
The present invention relates to a one-way clutch of roller type used as a part such as a torque transmitting element or a back stopper in a driving apparatus of a motor vehicle, an industrial machine and the like, for example.
2. Related Background Art
In general, a one-way clutch of roller type is comprised of an outer race having at least one pocket provided at its inner periphery with a cam surface, an inner race disposed in concentric with the outer race and having an outer peripheral track surface, a roller disposed within the pocket and adapted to transmit torque between the outer peripheral track surface of the inner race and the inner peripheral cam surface of the outer race, and a spring disposed within the pocket between the outer race and the roller and adapted to bias the roller toward an engagement direction with respect to the cam surface. 
With this arrangement, in the one-way clutch of roller type, the inner race is designed so as to be rotated only in one direction with respect to the outer race by means of a cam mechanism constituted by the roller and the cam surface. That is to say, the inner race is designed so that it is idly rotated relative to the outer race in one direction, and on the other hand, it applies rotational torque to the outer race via the cam mechanism only in an opposite direction.
An example of a spring used in such a one-way clutch of roller type is shown in FIG. 8. FIG. 8 is a view similar to a sectional view taken along the line 5-5 of FIG. 4.
As shown in FIG. 8, one end and the other end of a spring 55 are constituted by tab portions 65 and 66 bent with respect to a main body portion 77, respectively, and the tab portion 65 is locked to an axial end face 72 of an outer race 51 and the tab portion 66 is pinched between an axial end face of a roller 53 and a flange portion (not shown) of a cage.
Here, a bent portion i.e. connection portion 75 between the tab portion 65 and the main body portion 77 is provided to abut against an edge portion of the outer race 51 and a connection portion 76 between the tab portion 66 and the main body portion 77 is provided to abut against an edge portion of the roller 53.
In this way, when the connection portions abut  against associated members such as the outer race and roller to interfere with the associated members, during an operation of the one-way clutch, unnecessary forces are applied to the connection portions, with the result that the connection portions may be damaged due to fatigue or prematurely damaged due to wear and a smooth movement of the roller may be obstructed, thereby reducing reliability of the one-way clutch.
Further, in the one-way clutch of roller type, to obtain positive engagement, the roller as a torque transmitting member and the spring for biasing the roller must be prevented from being dislodged from the pocket in an axial direction and a radial direction.
For example, in a one-way clutch used as a starter of a motor bike, as disclosed in Japanese Patent Application Laid-open No. 2007-064475, it has been proposed to provide side plates on both sides of an outer race to prevent dislodgement of roller and spring.
In the conventional one-way clutch of roller type, since the connection portions between the tab portions and the main body portion of the spring abut against the associated member such as the outer race and roller to interfere with the associated members, during the operation of the one-way clutch, the unnecessary forces are applied to the connection portions, with the result that the connection portions may be damaged due to the fatigue or prematurely damaged due to the wear and the smooth movement  of the roller may be obstructed, thereby reducing the reliability of the one-way clutch.
On the other hand, as disclosed in the above-mentioned Japanese Patent Application Laid-open No. 2007-064475, it was necessary to provide the side plates on both axial sides of the outer race to prevent the dislodgement of the roller and the spring. Further, in a condition before the one-way clutch is mounted on the inner race, there must be provided separately means for dislodging the roller and the spring in a radial direction. In any cases, it is difficult to reduce the cost of the clutch.
Accordingly, it is desired to provide a one-way clutch of roller type which has enhanced reliability in engagement and idle rotation of the one-way clutch and can reduce the cost in comparison with conventional clutches and which includes means for preventing roller and spring from being dislodged.